Electric switch

ABSTRACT

An electric switch comprises an insulating housing containing a movable contact operably connected to a finger operated pivotable actuator. The movable contact is formed as a resilient arcuate metal strip mounted at one end to the actuator such that the convex surface of the arcuate strip faces away from the actuator. A contact surface is formed on the convex surface of the arcuate strip adjacent the free end of the arcuate strip. The actuator is movable under finger pressure to two pivoted positions, one in which the movable contact surface disengages a stationary contact mounted in the bottom of the housing and one in which it engages the stationary contact.

United States Patent [191 [30] Foreign Application Priority Data May 14,1974 Spain 414752 [52] US. Cl 200/164 A; 200/241; 200/339 [51] Int. Cl.HOIH l/18 [58] Field of Search 200/339, 292, 159 A, 8 A, 200/6 C, 164 R,164 A, 153 LA, 153 LB,

[56] References Cited UNITED STATES PATENTS 1,679,192 7/1928 Wheeland200/8 A 2,681,393 6/1954 Hopkins 200/8 A 3,471,663 10/1969 Farrell eta]. 200/76 [451 Oct. 14, 1975 3,643,051 2/1972 Foley ZOO/164 A PrimaryExaminerRobert K. Schaefer Assistant ExaminerWilliam J. Smith Attorney,Agent, or FirmWilliam J. Keating; Jay L. Seitchik; Frederick W. Raring[57] ABSTRACT An electric switch comprises an insulating housingcontaining a movable contact operably connected to a finger operatedpivotable actuator. The movable contact is formed as a resilient arcuatemetal Strip mounted at one end to the actuator such that the convexsurface of the arcuate strip faces away from the actuator. A Contactsurface is formed on the convex surface of the arcuate strip adjacentthe free end of the arcuate strip. The actuator is movable under fingerpressure to two pivoted positions, one in which the movable contactsurface disengages a stationary contact mounted in the bottom of thehousing and one in which it engages the stationary contact.

1 Claim, 5 Drawing Figures US. Patent Oct. 14, 1975 Sheet 2 of33,912,895

US. Patent oci. 14,1975 Sheet 3 of3 3,912,895

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ELECTRIC SWITCH This invention relates to electric switches, and moreparticularly concerns a switch having a movable contact which is drivenby a finger operated actuator to predetermined pivoted positions to makeor break engagement with a stationary contact or contacts.

The present invention is an electric switch comprising a housing ofinsulating material, a movable contact mounted in the housing and beingformed as a resilient arcuate metal strip having a contact surfaceformed on the convex surface of the arcuate strip adjacent a free end ofthe arcuate strip for contacting at least one stationary contact, and anactuator to which the arcuate strip is directly connected at its otherend with the convex surface of the arcuate strip facing away from theactuator, the actuator being pivotably mounted in the housing and beingmovable by finger pressure between a first pivoted position in which thecontact surface is in a position corresponding to disengagement with thestationary contact and a second pivoted position in which the contactsurface is in a position corresponding to engagement with the stationarycontact.

An embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of an assembled switch according to theinvention;

FIG. 2 is an exploded perspective view of the switch of FIG. 1;

FIG. 3 is a sectional view taken on line A--A showing the switch in anon condition;

FIG. 4 is a sectional view similar to FIG. 3 but showing the switch inan off condition; and

FIG. 5 is an enlarged diagrammatic view illustrating an improvement tothe switch of FIG. 1.

With reference firstly to FIGS. 1 and 4, the switch comprises a housing1 of resilient insulating plastics material, a finger operated rockeractuator 2, a movable metal contact 4 and a bottom plate 5 of insulatingplastics material.

The housing 1 is shaped generally as a rectangular box open at its topend 7 and its bottom end 8 and having on each of two opposed sides 9 anintegral panel mounting rib 10 tapering from a relatively thick portionadjacent the top end 7 of the housing to a relatively thin portionadjacent the bottom end 8 of the housing. A peripheral flange 11 extendsfrom the top end 7 of the housing, the flange having a rim 12 disposedin parallel spaced relationto the walls of the housing.

A front wall 15 is provided at the bottom end 8 of the housing with twospaced mounting arms 16 extending below the housing and terminating in awedge-shaped detent 17. Two similar mounting arms, one of which is shownin FIG. 2, are provided on the rear wall 18 of the housing.

The front wall 15 and rear wall 18 are each provided with a throughaperture 20 disposed intermediate the sides 9 and adjacent the top end 7of the housing. Each aperture forms a recess in the adjacent portion ofthe flange l1 and a semi-circular bearing surface 21.

Located in the corner defined by the left-hand (as seen in FIGS. 3 and4) housing side 9, the front wall 15 and the bottom plate 5 is aprojection 22 defining a stop shoulder 23 facing the top end 7 of thehousing, the projection being integrally formed with the housing. Asimilar projection 22 is formed in the corner defined by the right-hand(as seen in FIGS. 3 and 4) housing side 9, the rear wall 18 and thebottom plate 5.

The rocker actuator 2 is a hollow plastics molding and has a V-shapedfinger engaging portion 25 formed between two arcuate surfaces 26. Fromeach of two sides 27 of the actuator 2 extends a cylindrical boss ortrunnion 28 one of which can be seen in FIG. 2.

An abutment surface 29 is formed at the end of each arcuate surface 26remote from the finger engaging portion 25. A slot 30 extends inwardlyof the underside of the actuator 2 from a position adjacent one of theabutment surfaces 29 in a direction towards the finger engaging portion25, the slot being formed in a thickened portion 31 of the actuator 2.

The movable contact 4 is an arcuate metal strip having barbs 33 adjacentone of its free ends. The other free end is formed generally as aV-shaped bifurcated to form two spaced contact portions 34 each of whichhas a downwardly directed dimple 35 serving as a contact surface.

The bottom plate 5 is generally rectangular with two spaced notches 46in each of the longer edges 47, the notches being complementary in shapeto the wedgeshaped detents 17 on the arms 16 of the housing. Two alignedthrough holes in the plate 5 receive stationary contacts 48 which havetabs 49 projecting from the lower surface of the plate 5 for connectionto circuitry (not shown) to be controlled by the switching and contactsurfaces 50 lying just proud of the upper surface of the plate 5.

Assembly of the switch is carried out as follows: The movable contact 4is assembled to the actuator 2 by pushing the end of the contactcontaining the barbs 33 into the slot 30, the barbs engaging the sidesof the slot to secure the contact to the actuator.

The two components thus assembled are then inserted through the top end7 of the housing 1 until the trunnions 28 on the actuator 2 engage theflange 11 where they are recessed by the apertures 20. Application ofdownward pressure on the actuator 2 causes the walls 15 and 18 of thehousing to flex outwardly so that the trunnions 28 snap on to thebearing surfaces 21 of the apertures 20 and under the flange 11. In thisassembled condition, the finger engaging portion 25 is disposed abovethe top end 7 of the housing 1, the arcuate surfaces 26 substantiallyclosing the top end 7.

The bottom plate 5 is then mounted to the bottom end 8 of the housing 1by snapping resiliently the detents 17 of the mounting arms 16 under theplate 5, the arms 16 being received in the notches 46 in the plate 5.This completes assembly of the switch.

The switch has two distinct pivoted positions. To achieve the first, theleft-hand part of finger engaging portion 25 of the actuator 2 isdepressed causing the actuator to be rotated anti-clockwise from theposition of FIG. 3 to that of FIG. 4 in which the contact portions 34are out of engagement with the stationary contacts 48 in the bottomplate 5 and in which the left-hand abutment surface 29 engages theleft-hand shoulder 23 of the housing. It is noted that initially themovable contact resiliently opposes rotation of the actuator 2 but thereis an angular position after which the spring force acting between thecontact 4 and the bottom plate 5 acts in a direction to assist theanti-clockwise rotation so that a toggle action providing positive biasto the fully off position is present. By depressing the right-hand halfof the finger-engaging portion 25 of the actuator 2, the actuator isrotated clockwise from the position of FIG. 4 to that of FIG. 3,engagement of the right-hand abutment surface 29 with the right-handshoulder 23 of the housing limiting the extent of clockwise rotation ofthe actuator. In this position, the dim ples 35 of the contact 4 are inengagement with the contact surface 50 of respective stationary contacts48. Again it is noted that initial clockwise rotation is opposed by thecontact 4 but after the over-center toggle position is reached theactuator is biased to the fully on position of FIG. 3.

FIG. 5 shows diagrammatically an improved form of the switch of FIGS. 1to 4 in which like parts bear like reference numerals. Extending fromeach lateral edge of the contact 4 is a curved portion 52 integral withthe contact 4. The housing 1 is provided with two similar guide members53, only one of which is shown, spaced one on each side of the path ofmovement of the contact 4, the guide member 53 being integrally formedwith the walls and 18, respectively, of the housing 1. Each guide member53 has a curved cam surface 54 facing the top end 7 of the housing.

As the contact 4 is moved from the on or closed position shown in fulllines to the off or open position shown in phantom by depressing theactuator as described above, the curved portions 52 of the contact 4engage the cam surface 54 of respective guide members 53 and the freeend portion of the contact 4 is cammed upwardly so that the dimples 35leave the contact surfaces 50 and follows the path marked by arrows inFIG. 5. The cam surfaces 54 are so shaped that near the end of theanti-clockwise rotation the curved portions 52 leave the lower end ofthe cam surfaces and the contact portions 34 drop into the positionshown in phantom in which the dimples 35 engage the bottom plate 5.Movement of the contact 4 from the off position shown in phantom to theon position is obviously effected in a manner reverse to that describedabove, the contact portions 34 dropping on to the contact surfaces 50 asthe curved portions 52 leave the upper end of the cam surfaces 54. Asthe dimples 35 are lifted clear of the bottom plate 5 during switchingbetween the two positions, wear is reduced to a minimum. It is notedthat, in this case, the positive detent action ensuring a fully on" orfully off condition is achieved by action of the cam surfaces 54 on thecurved portions 52.

The switch of the invention may be modified by providing another pair ofstationary contacts in the bottom plate 5 so that when the actuator isin the position shown in FIG. 4 the contact 4 bridges the other pair ofstationary contacts. In this modification a lateral groove may beprovided in the bottom plate 5 between the two pairs of stationarycontacts. The switch will, therefore, have three positions; one in whichone pair of stationary contacts is closed, one where the other pair isclosed, and an intermediate position in which both pairs are open.

In another modification, the movable contact 4 is made longer than inthe specific embodiment described which has the effect of continuouslybiasing the switch to one of the two extreme angular positions. It canbe arranged that the switch is biased to the off position and ismaintained in the on position only when finger pressure is maintained onthe actuator 2.

The switch described has only one movable contact 4; in a modification afurther movable contact identical with the first movable contact may bereceived in a slot similar to slot 30 specially provided for thatpurpose in a thickened portion 31' (indicated in FIGS. 3 and 4) on theother side of the trunnions 28 from the thickened portion 31, thefurther movable contact curving in an opposite sense to the firstmovable contact. The two movable contacts are not in alignment but areso arranged that they move along parallel spaced paths. The bottom plate5 is provided with a further pair of stationary contacts spaced from thefirst pair and lying in the path of the further movable contact so thatwhen the first movable contact is in the on position with respect to itsassociated pair of stationary contacts the further movable contact is inthe of position with respect to its associated pair of stationarycontacts and vice versa.

Instead of using the bottom plate 5, the switch could be clampeddirectly on the surface of a printed circuit board for making andbreaking connection with a selected conductor or conductors on thecircuit board. Alternatively, the bottom plates could be moldedintegrally with the housing.

When the three-position modification as described above is combined withthe improvement shown in FIG. 5, a stable intermediate position in whichboth pairs of contacts are open is obtained by providing a recess oneach cam surface in which recesses the curved portions 52 may bereceived.

What is claimed is:

1. An electric switch comprising a housing of insulating material, amovable contact mounted in the housing and being formed as a resilientarcuate metal strip having a contact surface formed on the convexsurface of the arcuate strip adjacent a free end of the arcuate stripfor contacting at least one stationary contact, and an actuator to whichthe arcuate strip is directly connected at its other end with the convexsurface of the arcuate strip facing away from the actuator, the actuatorbeing pivotably mounted in the housing and being movable by fingerpressure between a first pivoted position in which the contact surfaceis in a position corresponding to disengagement with the stationarycontact and a second pivoted position in which the contact surface is ina position corresponding to engagement with the stationary contact, saidhousing having two shoulders engageable with respective abutmentsurfaces on the actuator to define the first pivoted position and thesecond pivoted position of the actuator, said housing further having twosimilar guide members spaced one on each side of the path of movement ofthe arcuate strip, each guide member having a cam surface engageablewith a respective portion on the arcuate strip, the guide membersserving to cam the free end portion of the arcuate strip upwardly fromthe bottom of the housing while the actuator is between the first andsecond pivoted positions.

1. An electric switch comprising a housing of insulating material, amovable contact mounted in the housing and being formed as a resilientarcuate metal strip having a contact surface formed on the convexsurface of the arcuate strip adjacent a free end of the arcuate stripfor contacting at least one stationary contact, and an actuator to whichthe arcuate strip is directly connected at its other end with the convexsurface of the arcuate strip facing away from the actuator, the actuatorbeing pivotably mounted in the housing and being movable by fingerpressure between a first pivoted position in which the contact surfaceis in a position corresponding to disengagement with the stationarycontact and a second pivoted position in which the contact surface is ina position corresponding to engagement with the stationary contact, saidhousing having two shoulders engageable with respective abutmentsurfaces on the actuator to define the first pivoted position and thesecond pivoted position of the actuator, said housing further having twosimilar guide members spaced one on each side of the path of movement ofthe arcuate strip, each guide member having a cam surface engageablewith a respective portion on the arcuate strip, the guide membersserving to cam the free end portion of the arcuate strip upwardly fromthe bottom of the housing while the actuator is between the first andsecond pivoted positions.